diff mbox series

[net-next,01/13] af_unix: Use offsetof() instead of sizeof().

Message ID 20211106091712.15206-2-kuniyu@amazon.co.jp (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series af_unix: Replace unix_table_lock with per-hash locks. | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 4 this patch: 4
netdev/cc_maintainers warning 3 maintainers not CCed: yajun.deng@linux.dev dsahern@kernel.org viro@zeniv.linux.org.uk
netdev/build_clang success Errors and warnings before: 0 this patch: 0
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 4 this patch: 4
netdev/checkpatch warning WARNING: line length of 84 exceeds 80 columns WARNING: line length of 93 exceeds 80 columns WARNING: line length of 96 exceeds 80 columns
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Iwashima, Kuniyuki Nov. 6, 2021, 9:17 a.m. UTC
The length of the AF_UNIX socket address contains an offset to the member
sun_path of struct sockaddr_un.

Currently, the preceding member is just sun_family, and its type is
sa_family_t and resolved to short.  Therefore, the offset is represented by
sizeof(short).  However, it is not clear and fragile to changes in struct
sockaddr_storage or sockaddr_un.

This commit makes it clear and robust by rewriting sizeof() with
offsetof().

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp>
---
 net/unix/af_unix.c | 15 ++++++++-------
 net/unix/diag.c    |  3 ++-
 2 files changed, 10 insertions(+), 8 deletions(-)
diff mbox series

Patch

diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 78e08e82c08c..b0ef27062489 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -231,7 +231,7 @@  static int unix_mkname(struct sockaddr_un *sunaddr, int len, unsigned int *hashp
 {
 	*hashp = 0;
 
-	if (len <= sizeof(short) || len > sizeof(*sunaddr))
+	if (len <= offsetof(struct sockaddr_un, sun_path) || len > sizeof(*sunaddr))
 		return -EINVAL;
 	if (!sunaddr || sunaddr->sun_family != AF_UNIX)
 		return -EINVAL;
@@ -244,7 +244,7 @@  static int unix_mkname(struct sockaddr_un *sunaddr, int len, unsigned int *hashp
 		 * kernel address buffer.
 		 */
 		((char *)sunaddr)[len] = 0;
-		len = strlen(sunaddr->sun_path)+1+sizeof(short);
+		len = strlen(sunaddr->sun_path) + offsetof(struct sockaddr_un, sun_path) + 1;
 		return len;
 	}
 
@@ -970,7 +970,7 @@  static int unix_autobind(struct socket *sock)
 		goto out;
 
 	err = -ENOMEM;
-	addr = kzalloc(sizeof(*addr) + sizeof(short) + 16, GFP_KERNEL);
+	addr = kzalloc(sizeof(*addr) + offsetof(struct sockaddr_un, sun_path) + 16, GFP_KERNEL);
 	if (!addr)
 		goto out;
 
@@ -978,7 +978,8 @@  static int unix_autobind(struct socket *sock)
 	refcount_set(&addr->refcnt, 1);
 
 retry:
-	addr->len = sprintf(addr->name->sun_path+1, "%05x", ordernum) + 1 + sizeof(short);
+	addr->len = sprintf(addr->name->sun_path + 1, "%05x", ordernum) +
+		offsetof(struct sockaddr_un, sun_path) + 1;
 	addr->hash = unix_hash_fold(csum_partial(addr->name, addr->len, 0));
 	addr->hash ^= sk->sk_type;
 
@@ -1160,7 +1161,7 @@  static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
 	    sunaddr->sun_family != AF_UNIX)
 		return -EINVAL;
 
-	if (addr_len == sizeof(short))
+	if (addr_len == offsetof(struct sockaddr_un, sun_path))
 		return unix_autobind(sock);
 
 	err = unix_mkname(sunaddr, addr_len, &hash);
@@ -1604,7 +1605,7 @@  static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int peer)
 	if (!addr) {
 		sunaddr->sun_family = AF_UNIX;
 		sunaddr->sun_path[0] = 0;
-		err = sizeof(short);
+		err = offsetof(struct sockaddr_un, sun_path);
 	} else {
 		err = addr->len;
 		memcpy(sunaddr, addr->name, addr->len);
@@ -3235,7 +3236,7 @@  static int unix_seq_show(struct seq_file *seq, void *v)
 			seq_putc(seq, ' ');
 
 			i = 0;
-			len = u->addr->len - sizeof(short);
+			len = u->addr->len - offsetof(struct sockaddr_un, sun_path);
 			if (!UNIX_ABSTRACT(s))
 				len--;
 			else {
diff --git a/net/unix/diag.c b/net/unix/diag.c
index 7e7d7f45685a..db555f267407 100644
--- a/net/unix/diag.c
+++ b/net/unix/diag.c
@@ -19,7 +19,8 @@  static int sk_diag_dump_name(struct sock *sk, struct sk_buff *nlskb)
 	if (!addr)
 		return 0;
 
-	return nla_put(nlskb, UNIX_DIAG_NAME, addr->len - sizeof(short),
+	return nla_put(nlskb, UNIX_DIAG_NAME,
+		       addr->len - offsetof(struct sockaddr_un, sun_path),
 		       addr->name->sun_path);
 }